By means of the articulated connection of longitudinal member and transverse member of an undercarriage frame it is possible to achieve an improvement in respect of the risk of derailment compared with rigid undercarriage frames.
An undercarriage of said type having an H-shaped, deformable frame, consisting of two longitudinal members and one transverse member, is described in DE 43 06 848 A1 and in EP 0 409 128 A1. In the arrangement proposed therein shearing forces are introduced into the undercarriage frame by way of wheelset bearings which are rigidly connected to the longitudinal members.
WO 90/11216 discloses an undercarriage with articulated frame having at least one transverse member which is arranged between two longitudinal members and spring-mounted to cushion against the longitudinal members. In this case, too, occurring shearing forces which may be caused by steering actions are introduced by way of wheelset bearings which are rigidly connected to the longitudinal members.
In the undercarriages that have just been cited, shearing forces, such as may occur for example when curves are negotiated, are introduced into the undercarriage frame by way of wheelset bearings which are connected to the longitudinal members of the undercarriage frame, which means that the undercarriage frame should be as resistant to deformation as possible with respect to said shearing forces in order to ensure stable running.
A disadvantageous aspect of said embodiment variants is that the desired resistance to shearing forces between the wheelsets cannot be achieved therewith.
A deformation-resistant undercarriage frame is known from EP 1276653 B1 in which the wheelset bearings are connected to the transverse member or, as the case may be, to one of the transverse members of the rail vehicle in each case.
As a result the shearing forces occurring are introduced by way of the wheelset bearings directly into the respective transverse member. Since the transverse member has a much higher shear resistance with respect to the occurring lateral loads than the longitudinal members, the stiffness properties of the undercarriage and consequently the stable running characteristics are substantially improved thereby.